package bat.iog.oop.innerclass;

// innerclasses/Callbacks.java
// Using inner classes for callbacks
// {java innerclasses.Callbacks}
interface Incrementable {
    static String abc = null;
    default void incrementc() {
        System.out.println("Other operation");
    }
    static void incrementd() {
        System.out.println("Other operation");
    }
    void increment();
}

// Very simple to just implement the interface:
class Callee1 implements Incrementable {
    private int i = 0;
    @Override
    public void increment() {
        i++;
        System.out.println(i);
    }
}
class MyIncrement {
    public void increment() {
        System.out.println("Other operation");
    }
    static void f(MyIncrement mi) { mi.increment(); }
}
// If your class must implement increment() in
// some other way, you must use an inner class:
class Callee2 extends MyIncrement {
    private int i = 0;
    @Override
    public void increment() {
        super.increment();
        i++;
        System.out.println(i);
    }
    
    private class Closure implements Incrementable {
        @Override
        public void increment() {
            // Specify outer-class method, otherwise
            // you'll get an infinite recursion:
            Callee2.this.increment();
        }
    }
    Incrementable getCallbackReference() {
        return new Closure();
    }
}
class Caller {
    private Incrementable callbackReference;
    Caller(Incrementable cbh) {
        callbackReference = cbh;
    }
    void go() { callbackReference.increment(); }
}
public class Callbacks {
    public static void main(String[] args) {
        Callee1 c1 = new Callee1();
        Callee2 c2 = new Callee2();
        MyIncrement.f(c2);
        Caller caller1 = new Caller(c1);
        Caller caller2 =
                new Caller(c2.getCallbackReference());
        caller1.go();
        caller1.go();
        caller2.go();
        caller2.go();
    }
}
